The present invention relation to embedded type speaker units mountable by being embedded in an opening section formed in a mounting part, such as a ceiling or side wall.
There have heretofore been known embedded type speaker units (such as ceiling speakers) that are installed or mounted by being embedded in an opening section formed in a ceiling or the like of a room, as disclosed for example in Japanese Patent Application Laid-open Publication No. 2014-017810 (hereinafter referred to as “the relevant patent literature”). Generally, such speaker units include a cabinet section of a substantially cylindrical shape, and a speaker face provided in the bottom surface of the cabinet section. To mount the speaker unit to a ceiling, for example, the cabinet section is inserted into a mounting hole (opening section) of the ceiling with the speaker face exposed on the face (i.e., lower surface) of the ceiling, and then the inserted cabinet section is fixed or fastened to the ceiling by fastening via bolts or the like. A mounting structure for such a speaker unit includes a provisionally fastening mechanism for preventing the heavy speaker unit from falling down accidentally or by mistake before the fastening via the bolts or the like or after cancellation of the fastening, as disclosed in the relevant patent literature.
In the speaker unit disclosed in the relevant patent literature, a plurality of the provisionally fastening mechanisms are provided for provisionally fastening the speaker unit in such a manner as to reliably prevent the speaker unit from accidentally falling down from the opening section (mounting hole). When the speaker unit is to be dismounted for maintenance or replacement, there arises a need to cancel the fastening, with respect to the mounting hole, of all of the provisionally fastening mechanisms. Because a human operator cannot simultaneously cancel the fastening of three or more provisionally fastening mechanisms, it has generally been conventional for the human operator to cancel with one hand the fastening of a particular one of the provisionally fastening mechanisms while retaining with the other hand one or some of already-canceled provisionally fastening mechanisms in a canceled state.
However, in a case where the speaker unit is heavy in weight and/or located at a high position, and if one hand of the human operator is occupied or busy with something else, safety of the human operator cannot be secured and the operation for mounting and dismounting the speaker unit cannot be performed efficiently in such situations.